So, not sure what the commercial ones look like, but I found some goose shells and they had a hole in the top that I presumed was for a stake. I took some 1/2 inch dowel for the stake and some 1/4 dowel for the "pin". Drilled a hole in the top of the 1/2 inch dowel and before inserting a piece of the 1/4 inch, I sort of rounded the top thinking it might make the shell spin/bob/generally move around some. Painted it flat black. Time will tell. Have no idea if it will work. Mostly posted b/c you didn't have any other replies. Good luck.
Basically did the same thing as above except instead of drilling and gluing I just used a bench grinder and turned down the diameter at the top of the 1/2" dowel until it fit into the hole in the deke. Then I used the grinder to put a point on the other end of the dowel to make it easier to shove into the ground. They've worked for 3 seasons now without fail.
Don't normally have an issue just jamming them into the ground even when it gets cold. And generally around here by the time the ground gets really hard we've usually got a pretty good cover of snow and I just don't use stakes at that point (I more or less use stakes not so much for motion but to get the shells up out of the stubble and more visible, which isn't all that necessary when you have a good thick layer of snow)